1. Field of the Invention
The present invention relates generally to a method for determining a position of a marine vessel and, more particularly, to a method by which devices on a marine vessel can obtain information, in cooperation with fixed devices on shore, to allow a determination of the relative position and attitude of the marine vessel relative to a fixed location, such as a dock.
2. Description of the Related Art
Many different types of navigation and docking systems are known to those skilled in the art.
U.S. Pat. No. 3,690,767, which issued to Missio et al. on Sep. 12, 1972, describes an optical tanker docking system. The docking system is intended for large ocean going vessels. It comprises a laser pulse range radar system having a laser transmitter and receiver, a retroreflector, and receiving and transmitting optics. Two such systems are disposed on a dock. The retroreflectors are disposed at the bow and stern of a vessel. The laser systems share a time interval meter, a computer, and a display panel. The lasers track the retroreflectors as the ship approaches the dock and the time interval between the transmitted and received pulses is measured. Computations are made in the velocity of the approaching vessel, its distance from the dock, and the vessel position with reference to the dock are continually displayed. The information is then transmitted to the ship's captain.
U.S. Pat. No. 3,707,717, which issued to Frielinghaus on Dec. 26, 1972, describes a boat berthing monitor incorporating sonar and Doppler radar techniques. The system generates correction command signals relative to the berthing velocity profile of a vehicle in approach of a docking station. A Doppler radar system includes a radar transceiver. It projects signals between the docking position and the vehicle and respondingly generates Doppler shift frequency signals indicative of the velocity of the vehicle and the relative displacement thereof. A radar counter has preset initial counts stored therein which are indicative of anticipated initial berthing conditions and responds to the frequency shift signals by counting down from the initial counts in accordance with the Doppler shift.
U.S. Pat. No. 5,274,378, which issued to O'Conner on Dec. 28, 1993, describes a docking velocity indicator system. A relative velocity indicator system for assistance in the docking of vessels uses a radar sensor providing a relative velocity signal indicative of the relative velocity between a ship and a reference, such as a dock. A wireless transmitter associated with the radar sensor receives the relative velocity signal and transmits a signal indicative of the relative velocity signal. A portable receiver and indicator unit carried by the captain of the vessel has a receiver for receiving the transmitted signal and an indicator arranged to receive, from the receiver, a receiver signal indicative of the transmitted signal and, thereby, of the relative velocity signal for indicating the relative velocity between the ship and the reference.
U.S. Pat. No. 5,933,110, which issued to Tang et al. on Aug. 3, 1999, describes a vessel attitude determination system and method. A portable attitude determination apparatus and method are disclosed that can be used with a ship docking system. At least two receivers on a vessel receive global positioning system (GPS) satellite data. GPS carrier phase measurements are used to determine attitude of a moving platform. The phase measurements are processed to determine a precise vector from one receiver phase center to the other. The azimuth and elevation of a baseline vector is then computed.
U.S. Pat. No. 6,268,829, which issued to Weckstrom on Jul. 31, 2001, describes a Doppler direction finder and method of location using Doppler direction finder. It comprises at least one antenna spaced from a location point. The antenna is arranged in use to be rotated about the rotation point. The antenna is arranged to provide a first output signal comprising a signal received by the antenna combined with the Doppler shift component. There are means for providing a second output signal comprising the received signal without the Doppler shift component. Processing means process the first and second signals to obtain the Doppler shift component. Determining means determine from the Doppler shift component the direction from which the received signal is received.
U.S. Pat. No. 6,492,933, which issued to McEwan on Dec. 10, 2002, describes an SSB pulse Doppler sensor and active reflector system. A dual channel microwave sensor employs single sideband Doppler techniques in innumerable vibration, motion, and displacement applications. When combined with an active reflector, the sensor provides accurate range and material thickness measurements even in cluttered environments.
U.S. patent application Ser. No. 11/248,482, which was filed on Oct. 12, 1995 by Bradley et al., discloses a marine vessel maneuvering system. The vessel is maneuvered by independently rotating first and second marine propulsion devices about their respective steering axes in response to commands received from a manually operable control device, such as a joystick. The marine propulsion devices are aligned with their thrust vectors intersecting at a point on a centerline of the marine vessel and, when no rotational movement is commanded, at the center of gravity of the marine vessel. Internal combustion engines are provided to drive the marine propulsion devices. The steering axes of the two marine propulsion devices are generally vertical and parallel to each other. The two steering axes extend through a bottom surface of the hull of the marine vessel.
U.S. patent application Ser. No. 11/248,483, which was filed on Oct. 12, 2005 by Bradley et al., discloses a vessel positioning system that maneuvers a marine vessel in such a way that the vessel maintains its global position and heading in accordance with a desired position and heading selected by the operator of the marine vessel. When used in conjunction with a joystick, the operator of the marine vessel can place the system in a station keeping enabled mode and the system then maintains the desired position obtained upon the initial change of the joystick from an active mode to an inactive mode. In this way, the operator can selectively maneuver the marine vessel manually and, when the joystick is released, the vessel will maintain the position in which it was at the instant the operator stopped maneuvering it with the joystick.
The patents described above are hereby expressly incorporated by reference in the description of the present invention.
A paper, titled “Direction Finding System” by Harry Lythall describes a roof mounted direction finding system which uses eight antennae for direction finding purposes. Appropriate circuitry is also described in the paper.
A product description pamphlet by the Banner Company describes a particular type of ultrasonic sensor which is available in commercial quantities and identified as the U-GAGE T30 series with analog and discreet outputs. Signals provided by these ultrasonic sensors allow a determination to be made regarding the distance between the sensor and an object that reflects signals transmitted by the sensors.